The invention relates to an eyelet button holing machine which is designed to stop by applying a stopper against rotation of the main shaft after reducing the main shaft speed from high to low speed.
According to conventional stopping mechanisms for eyelet button holing machines, a stopping cam provided at the main shaft and a stopping arm which engages with the stopping cam provide a hooking mechanism to stop the main shaft. The hook plunges into a recess portion of the stopping cam so that the main shaft is suddenly stopped.
In accordance with this type of eyelet button holing machine, if the ambient temperature is high (30.degree.-40.degree. C.), when the stopper arm acts to stop the main shaft after completion of an eyelet button holing, the hooking mechanism does not work smoothly and in the worst case, the hook is driven out from the stopper cam. The reason for such a malfunction is that the oil viscosity is lowered due to a high ambient temperature and the machine is therefore running at an unexpectedly higher speed when trying to suddenly stop the machine. Accordingly, the hook is kicked out by the stopper cam and the stitching can not terminate at a predetermined point. Conversely, if the ambient temperature is low (0.degree.-10.degree. C.), the machine speed is lowered due to the high oil viscosity and, when trying to stop the machine, it stops before terminating the last stitch due to the high oil viscosity.